Process of and apparatus for refrigeration



A. SCHWARZ March 20, 1934.

1,951,447 PROCESS OF AND APPARATUS FOR REFRIGERATION Filed April 18, 1930 2 Sheets-Sheet 1 JNVENTUR'. flUEZ/ST JEHWEKZ BY-$4M, in 9n flTTJENEJ IS March 20, 1934. A. SCHWARZ v PROCESS OF AND APPARATUS- FOR REFRIGERATION Filed April 18, 1930 2 Sheets-Sheet 2 oTnww/ooooooooo o OOOOTOOOOOOOOOO afoonwwobomodooo Fatented Mar, 20, 1934 usiran PROCESS OF AND APPARATUS FOR REFRIGERATION 14 Claims.

The present invention relates generally to an improved process of and apparatus for refrigeration, and has reference more particularly to a novel process of refrigeration embodying the use of cabon dioxide (CO2) as the refrigerant. In

certain respects, the present invention is a modification or improvement of that disclosed in my copending application Serial No. 429,176, filed February 1'7, 1930.

One of the objects of the present invention resides in a novel process of refrigeration in which carbon dioxide as the refrigerant is condensed and cooled by means of brine so that very low condenser and suction pressures, resulting in an exceptionally low temperature of vaporization, will be obtained.

Other objects reside in the provision of a new and improved process of refrigeration which comprises a plurality of stages for liquefying. and vaporizing the refrigerant to produce low temperatures by low condensing and suction pressures, and in the preferred form of which the low temperature refrigerant is carbon dioxide, and the refrigerating medium for condensing the carbon dioxide is ammonia.

Further objects are to provide a novel refrigerator plant which may be utilized to accomplish the foregoing objects, and which comprises an arrangement of pipes and valves, for connecting the various operating units, adjustable at will to produce selectively any one of a plurality of systems, for example, (1) a two stage system adapted to operate at different pressures depending on what refrigerants are employed, and (2) a single stage system in which the refrigerator is adapted to be connected in a closed circuit with either a water cooled condenser or a brine cooled condenser.

Other objects and advantages will become .apparent as the description proceeds.

In the accompanying drawings, Fig. 1 is a plan view of a plant embodying the principles of the invention:

Fig. 2 is a horizontal sectional view of a combination refrigerator and condenser shown in plan in Fig. 1:

Fig. 3 is a sectional view along the line 33 of Fig. 2:

Fig. 4 is a horizontal sectional View through a refrigerator, shown in plan in Fig. l: and

Fig. 5 is a horizontal sectional view through a condenser shown in plan in Fig. 1.

In the plant according to the present invention a condenser 12 is provided through which a arr FFECE RElSSM-p O l-T151940 refrigerant is forced by pressure exerted by a v compressor 14.

The refrigerant' flows from said compressor through a pipe line 45 in which valves 57 and 58 are located. The condenser 12 (see Fig. 5) has a pair of header tanks 27 and 28 and a plurality of condenser tubes 29 connecting said two header tanks. These tubes extend through the space 30 in the condenser 12; The liquefied refrigerant flows from the header tank 27 through pipes 46 and 81 and an expansion valve 82 into a combination refrigerator and condenser 11. This refrigerator unit 11 (see Figs. 2 and 3) consists of refrigerator tubes 17 connecting oppositely ar-' ranged header tanks 21 and 22. From the header tank 22, the refrigerant vapor is drawn off by the compressor 14 through pipes 77 and 44, and in said pipe line a plurality of shut-off valves 56, 78, '79, and are provided. In this manner the circuit of the refrigerant is closed.

The condenser 12 of this first refrigerator system is cooled by means of fresh water which is forced by a pump 36 into the space 30 in the condenser 12 through the pipe 108. From the space 30, the fresh water is drained off through a pipe 109. Suitable valves 119 and 120 are interposed respectively in the pipes 108 and 109.

For the second stage refrigerator system, a refrigerator 10 (see Fig. 4) is provided, having two oppositely located header tanks 24 and 25 which are connected with each other by means of a plurality of refrigerator pipes 23, extending through the space 26 in the refrigerator 10.

In the combination refrigerator and condenser unit 11, a plurality of condenser tubes 16 are arranged and extend at right angles between the refrigerator. tubes 17 as shown clearly in the Figures 2 and 3, the condenser tubes connecting two header tanks 19 and 20.

The refrigerant used in the second refrigerator system is CO2, and this refrigerant leaves the condenser tubes ,16 and the header tank 20 in the liquid condition through pipes 68 and 48, and flows through an expansion valve 64 into the refrigerator tubes 23. From here the refrigerant vapor is drawn 01f through pipes 40, 65, and 66 by a compressor 15, which recompresses and forces the refrigerant through a pipe line 67 into the header tank 19 and back into the CO2 con- .denser tubes 16. The above shows clearly that in the plant according to the present invention, two refrigerator stages are present, and that the CO2 in the condenser tubes 16 is cooled by means of the refrigerator tubes 17, that is, the refrigerant of the first refrigerator stage. Within the broad concept of the invention, any suitable refrigerant may be used in the first stage. If carbon dioxide is used as the refrigerant in the first stage, the pressure will be relatively high. Carbon dioxide is safe in use, and hence desirable as a refrigerant on shipboard. If ammonia is used as the refrigerant in the first stage, the

pressure therein will be relatively low. The use of ammonia in the first stage has the advantage that the pressure will be low, relatively little power will be required and in fact no more power will be required in the present split stage system, using ammonia in the first stage and carbon dioxide in the second stage than in a single stage high pressure plant using only carbon dioxide, in which the condenser is cooled by fresh water.

It will be understood that the pressure in the second stage CO2 condenser is subject to control by varying either the temperature or the amount of refrigerant therein. Thus, it is possible to operate the second stage condenser at a pressure higher or lower than from 300 to 350 pounds at a given temperature, for example 0 F., by respectively inc'reasing'or decreasing the amount of carbon dioxide employed. Also, the operating .pressure of the second stage condenser may be reduced below-or increased above the aforementioned pressure range by respectively decreasing or increasing the temperature in the condenser.

Obviously, the operating pressure may also be.

changed by' varying both the'temperatu're and the amount of carbondioxide employed.

Before starting the second refrigerator plant in which CO2 is used as a refrigerant, the CO2 in the condenser, tubes 16 in the combination tank will becooled down to about zero Fahrenheit by the refrigerant in the refrigerator tubes 17 of the first refrigerator system. If desired, a brine grees above zero Fahrenheit, this pressure will be reduced to about 300 to 350 pounds when the above mentioned temperature of zero Fahrenheit is obtained. That means that thepressure will be reduced about 66 percent when the-second refrigerator circuit is started, and the liquid CO2 will leave the condenser pipes 16 at this temperature, and will enter the refrigerator 10 at about the same temperature. In this refrigerator, the CO2 is vaporized at the expense of its latent heat. of vaporization, and is then drawn off nd recompressed by the compressor 15. Since this C92 enters the refrigerator at a very low temperature, and evaporates at a still lower temperaturathe suction pressure will be correspondingly low, so that the object of the invention is obtained, namelyr Low temperature is produced bylow condenser and suction pressure.

On account of the heat absorbed by the combination unit 11 from the atmospheric air and heat absorbed in the suction line to the compressor 15, the first refrigerator system or plant the CO2 condenser are placed closer together and are more in number than the condenser tubes 16.

By a pump 35, any suitable heat carrying medium may be forced through pipes 103, 104, the CO2 refrigerator space 26 and a pipe 105 to a cooling room (not shown). From the cooling room, this medium may be returned through pipes 100 and 101 to the pump 35. The flow of the heat carrying medium is controlled by valves 111 to 115 and 123. I

Extremely low temperatures may be produced by letting very little heat carrying medium pass through the CO2 refrigerator space 26, so that the suction pressure finally will be reduced to a partial vacuum in the CO2 suction line 40.

If desired, the tank 11 may be eliminated and the fresh water cooled condenser 12 may be connected directly with the CO2 refrigerator by means of the pipes 46, 47, 48, and expansion valve 64 and CO2 may be used in both plants as refrigerant. The CO2 in the refrigerator tubes 23 will then be drawn off and recompressed by the compressor 14 through the pipes 40, 65, 74, 43, and 44, and will be returned to the fresh water cooled condenser through the pipes 45. In this case the CO2 would 100 enter the refrigerator 10 at a higher temperature than described before, and in consequence, the suctionpressure would be correspondingly higher. Thus, the plant may be converted at will into a single stage system with carbon dioxide as the refrigerant.

The plant may also be operated as a single stage system with theunit 11 as a condenser. In this i event, brine would be-utilized as the cooling me-, dium. Thefresh water cooled condenser 12 with the compressor 14 can be disconnected by closing valves 55, 56, 60 and 83.

If the fresh water cooled condenser 12 is-to be used in connection with the refrigerator tubes" 17 in the tank 11, the valves 57 and 58 in the pipe line 45, valves 59 and 83 in the pipes 46 and 81, the valves 80, 79, and '78 in the pipe line 77 and the valve 56 in the pipe line 44 must be open. At the same time, valves 60 and 61 in the pipe 47 and a valve 55 in the. pipe 43 must be closed. To connect the CO2 refrigerator 10 with the condenser tubes 16 in tank 11, valves 50, 51, 69, 70, '71, '72, '13, 62 and 63 in the pipes 40, 65, 66, 6'7, 68 and 48 must be open. When, however, the fresh water cooled condenser 12 is to be connected directly with the CO2 refrigerator, the valves 83, 73,

80, and 78 must be closed whilethe valves 59, 60, 61, 62, 63, 50, 51, 69, 76, 75, 54, 55, and 56 have to be open.

It will be evident that I have provided a refrigerator plant which may be adjusted for use in different ways and which therefore is adapted to satisfy widely varying demands. I Thus, the entire plant, including both stages may be employed. In this event, brine may or may not be used in the refrigerator and condenser unit 11. If brine is used in the unit 11, it will be available at the temperature prevailing in the unit for use in the cooling room (not shown). Assuming that brine is circulated through the refrigerator 10, brine at I 11 respectively.

If the refrigeration requirements dropto such a point that the full capacity of the entire plant 5 is not needed, the plant may be converted into any one of a plurality of single stage systems of varying capacity. For example, one single stage system may include the refrigerator 10, the compressor 15, the condenser tube 16 in the unit 11 and the expansion valve 64, connected in series the order named, and utilizing either brine or fresh water as the condensing medium in the space 18 about the tubes 16 to obtain respectively relatively low or high condenser pressures. It will be understood that when brine is used as the condensing medium, it will be obtained from an outside source at a suitably low temperature.

As an alternative expedient, another single stage system may comprise the refrigerator 10, the compressor 14, the fresh water condenser 12 and the expansion valve 64, connected in series in the order named, with either ammonia as the refrigerant for low pressure operation, or carbon dioxide as the refrigerant for high pressure operation.

As a still furtherexpedient, a third single stage system may include the tubes 1'7 in the unit 11 as refrigerator tubes in contact with brine or any other fluid medium to be cooled, the compressor 14, the fresh water cooled condenser 12 and the expansion valve 82, connected in series in the order named, preferably with ammonia as the refrigerant.

Thus, the refrigerator plant by reason of its convertibility at will into any one of a plurality of single and double stage systems, has a flexible capacity adapted to satisfy widely varying refrigeration demands. When the refrigeration demands are small, it would be wasteful to operate the entire plant at its maximum capacity, and hence one of the various single stage systems, best suited to the particular demand, would be employed.

Having described my invention and how the same is to be used, I claim as new, and desire to secure by Letters Patent:

1. In a two stage refrigerator system and method for producing low temperatures by low condenser and suction pressures two refrigerator plants adapted'to cooperate with each other, the condenser of the first plant being cooled by fresh water, a combination refrigerator andcondenser tank consisting of a closed housing containing the refrigerator tubes of the first and the condenser tubes of the second plant with brine passages therebetween, a by-path connecting the pipe line, leading from the fresh water cooled condenser, -to the pipe conducting the liquid of low boiling point from the condenser tubes of the second plant to the refrigerator of the same plant, a second by-path connecting the suction line of the first plant with the suction line of the second plant, a valve adapted to prevent the entrance of the refrigerant into the refrigerator tubes of the first plant, another valve arranged in the suction line of the first plant before the junction of said line with the second by-path, a third valve inserted in the suction line of the second plant right behind the junction of the second'by-path with said line, a fourth valve in the pipe conducting the liquid refrigerant of low boiling point to the refrigerator of the second plant and located between the outlet of the condenser pipes of the second plant and the first by-path and a pair of valves in each of said by-paths, one adjacent each end of each by-path.

2. A refrigerator plant comprising, in combination, a primary system having arefrigerator, a compressor, a suction conduit connecting said refrigerator to said compressor, a control valve interposed in said conduit, a fresh water cooled condenserconnectedto said compressor, an expansion valve connected to discharge into said refrigerator, a discharge conduit connecting said condenser to said expansion valve, and a control valve interposed in said discharge conduit, a secondary system having a second refrigerator, a second compressor, a second suction conduit con-- necting said second refrigerator to said second compressor, a second condenser connected to said second compressor, said second condenser and said first mentioned refrigerator being juxtaposed for the transfer of heat from the former to the latter, a second expansion valve discharging into said second refrigerator, a second discharge conduit connecting said second condenser to said second expansion valve, a valve controlled connection between the second condenser and said second discharge conduit, and a control valve interposed in said second discharge conduit, a bypass conduit including a control valve leading from said second suction conduit at a point between said second refrigerator and said second mentioned compressor to said first mentioned suction conduit at a point between said first mentioned control valve and said first mentioned compressor, and a by-pass conduit including a control valve leading from said first mentioned discharge conduit at a point between said first refrigerator to said compressor, a fresh water cooled condenser connected to said compressor, an expansion valve connected to discharge into said refrigerator, and a discharge conduit connecting said condenser to said expansion valve, asecondary system having a second refrigerator, a

second compressor, a second suction conduit connecting said second refrigerator to said second compressor, a second condenser connected to said second compressor, said second condenser andsaid first mentioned refrigerator beingjuxtaposed for the transfer of heat from the former to the latter, a second expansion valve discharging into said second refrigerator, and a second discharge conduit connecting said second condenser to said second expansion valve, a by-pass conduit including a control valve-for connecting said two suction conduits, and a by-pass conduit including a control valve for connecting said two discharge conduits.

4. A refrigerator plant comprising, in combination, a primary system having a refrigerator, a compressor, a suction conduit connecting said refrigerator to said compressor, a fresh water cooled condenser connected to said compressor, an expansion valve connected to discharge into said refrigerator, and a discharge conduit connecting said condenser to said expansion valve, a secondary system having a second refrigerator, a second compressor, a second suction conduit connecting said second refrigerator to said second compressor, a second condenser connected to said second compressor, said second condenser and said first mentioned refrigerator being jux- 4 pass conduit including a control valve for connecting said two suction conduits, a control vave in said second suction conduit between said bypass conduit and said second compressor, a bypass discharge conduit including a control valve for connecting said discharge conduits, and a control valve in said second\di'scharge conduit between said second condenser and said by-pass discharge conduit.

5. A refrigerator plant comprising, in combination, a refrigerator, an expansion valve discharging to said refrigerator, and -two separate refrigerant paths connected between the outlet of said refrigerator and the 'inletof said valve, said paths being selectively available either singly or jointly, one path including a compressor and a brine cooled condenser, the other path including a compressor and a water cooled condenser.

6. A refrigerator plant comprising, in combination, a primary single stage system including a firstrefrigerator, acompressor, a condenser, and an expansion valve connected'in series in the order named, a second single stage system including a second refrigerator, a compressor, a second condenser and an expansion valve connected in series in the order named, said first refrigerator and said second condenser being juxtaposed, means for circulating brine between said first refrigerator and said second condenser to effect a heat exchange therebetween and to cool the brine to a low temperature for outside use, and means for circulating brine through said second refrigerator to cool it to a temperature below said first mentioned temperature for. out-' side use, said systems being operable singly or jointly at will.

7. A refrigerator plant comprising, in combination, a compressor, a condenser, the inlet of said condenser being connected to the discharge of said compressor, a refrigerating element connected to the discharge of said condenser, an expansion valve interposed between said condenser and said element, the discharge of said element being connected to the inlet of said compressor, a second compressor. a condenser element juxtaposed to said refrigerator element for the transfer of heat to the latter, a single closed housing for enclosing said refrigerating element and said last mentioned condenser elements, said condenser element being connected to the discharge of said second compressor, a refrigerator connected'to the discharge ends of said condenser and of said condenser element, a valve controlled by-pass between the outlet of the first condenser and the outlet of the condenser element whereby the refrigerant from said condenser and said condenser element is commin ber, means adapted to lead a medium to be conden'sed and cooled or a liquid to be cooled through said passages, a refrigerator element defining a plurality of closed passages extending through said chamber and adapted to expand and evaporate .a refrigerant therein to abstract heat from said first mentioned passages, and meansfor lead--' condenser of the second system to the refrigera tor of the first system, said first system having a much greater heat absorbing capacity than said second system so as to remove the heat taken up by the refrigerator of the second system and also to remove heat from the brine passing through said housing.

10. In a refrigerating apparatus, a combined refrigerator and condenser comprising, in combination with compressor means, a single closed housing defining a chamber, two opposed 'head- 1 ers respectively at two opposite walls of said housing and having means for introducing and withdrawing a refrigerant, a plurality of rows of spaced condenser tubes connecting said head ers and extending through said chamber, two opposed headers respectively at two other opposite walls of said housing and having means for expanding a refrigerant into one of said last mentioned headers, and a plurality of rows of spaced refrigerator tubes connecting said last mentioned headers and extending through said chamber, means for introducing brine into said chamber between said tubes, and means for in-' troducing and withdrawing brine from said chamber.

11. A two stage refrigeration apparatus consisting of two refrigerator plants, each plant comprising a compressor, a condenser, an expansion valve and a refrigerator arranged in the order named to form a closed refrigeration'cyclathe .first plant employing a refrigerant of high boiling point and the second plant employing a refrigerant of low boiling point, the refrigerator of one plant and the condenser of the other plant being arranged in a single closed housing to constitute a combined refrigerator-and condenser unit having free passages between the refrigerator and the condenser, valve controlled connections whereby one of said plants may be discon-q nected from the other plant and said combined refrigerator and condenser unit then made to function merely as a refrigerator unit, and means whereby a fluid medium is circulated through the free passages in said unit and to be cooled therein for outside use.

12. In a multiple stage refrigeration system, a combined refrigerator and condenser unit consisting of a closed housing provided with two sets of tubes arranged in close relation and having free passages therebetween, the tubes of one set being refrigerator tubesmof one stage and the tubes of the other set being condenser tubes of the other stage, the refrigerator tubes of one stage being made to have greater heat absorbing capacity than'the condenser tubes of the second stage and also having a greater heat absorbing capacity than the refrigerator tubes of the second stage, and means for circulating a fluid medium through said passages in contact with both sets of tubes and for conveying the fluid medium to and away from said housing.

13. The process of producing low temperature without'vacuum operation which consists in compressing, condensing, expanding and vaporizing ous cycle, circulating a refrigerant of low boiling point in a second path in a continuous cycle, and in juxtaposition to the first path, utilizing the expanded temperature of the refrigerant in the first path to greatly reduce the pressure and. temperature of the refrigerant on the high side of the second path, maintaining the low pressure and low temperature on the high side of the second path during operation, thereby greatly reducing the power required in said second path, expanding the low temperature refrigerant of relatively low pressure by a correspondingly low suction pressure, circulating a fluid medium about the low side of the second path, circulating a fluid medium in contact with the juxtaposed portions of the two paths, and utilizing the fluid medium from the juxtaposed portions and from the low side of the second path for outside use whereby fiuidmedium of different temperatures may be available.

14. The process of producing low temperature without vacuum operation which consists in compressing, condensing, expanding and vaporizing a volatile refrigerant in one path in a continuous cycle, circulating a refrigerant of low boiling point in a second path in a continuous cycle and in juxtaposition to the first path, utilizing the expanded temperature of the refrigerant in the first path to greatly reduce the pressure and. tempera- 

